1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a liquid crystal display device for mounting a chip on glass (COG) to facilitate an array check.
2. Discussion of the Related Art
Generally, many methods for mounting a driving integrated circuit (IC) exist which provide a signal for driving an LCD device. Such methods include the wire bonding (WB) type, the tape automated bonding (TAB) type, and the COG-type.
The WB type method connects a panel electrode with a driving IC using Au wire. The TAB-type method mounts a package on a panel, in which a driving IC is connected to a film carrier. The COG-type method mounts a bump formed on a bare chip for a panel having an inner lead pad and an outer lead pad.
During the process steps of forming an LCD device, electrostatic discharge occurs in an internal TFT-LCD array, which destroys internal devices, such as a thin film transistor. For this reason, a shorting bar has been used to prevent the internal devices from being destroyed by the electrostatic discharge and facilitate array checking after forming an array region of a TFT-LCD.
In general, a first shorting bar is connected to respective gate lines and a second shorting bar is connected with respective data lines. A power source is applied to the shorting bar bar connected to the gate lines to check for open lines at end of the respective gate lines opposite to the shorting bar when performing a continuity check of the array. A similar technique is also applied to the data lines.
The shorting bar is not actually used in driving the TFT-LCD. The shorting bar is removed once it has performed the functions of protecting the TFT-LCD from electrostatic discharge and checking the array for continuity. In other words, if the array continuity check is successful after forming the TFT-LCD array, a top plate of the TFT-LCD and a bottom plate thereof are bonded to each other. The shorting bar is removed by a scribe and a grinding process.
Meanwhile, the respective gate lines and the respective data lines have different configurations from each other depending on the method utilized for mounting the driving IC, which causes difficulty in forming the shorting bar. In the TAB-type method for mounting a driving IC, the carrier film is connected to both sides of a bare chip so that a space on the TFT-LCD panel is ensured. In this case, a shorting bar is formed at one side of each of a gate line pad and a data line pad, which serves as driving IC mounting regions. In the COG-type mounting method, the inner lead and the outer lead should be formed within the driving IC mounting region of the TFT-LCD panel, because it is difficult to ensure a space on the TFT-LCD panel, thereby causing difficulty in forming a shorting bar in the driving IC mounting region. To overcome the above-mentioned shortcoming, a method for mounting a shorting bar using the COG-type mounting method has been recently developed.
A conventional method for mounting a shorting bar in an LCD device employing the COG-type mounting method will be described with reference to FIG. 1, which is a schematic layout illustrating a conventional LCD device employing a COG-type mounting method.
As illustrated in FIG. 1, a plurality of gate lines 1 are formed on a substrate in one direction at a predetermined interval and a plurality of data lines 2 are formed in a direction perpendicular to the gate lines 1 at a predetermined interval. Gate line pads 3 and data line pads 4 are respectively formed at one end of each of the respective gate lines 1 and data lines 2. A plurality of gate input pads 7 are formed at a predetermined interval opposite the gate line pads 3. A plurality of data input pads 8 are formed at a predetermined interval opposite the data line pads 4.
A gate driving IC mounting region 9 includes the gate line pads 3 and the gate input pads 7. A data driving IC mounting region 10 includes the data line pads 4 and the data input pads 8. In these driving IC mounting regions 9 and 10, first and second shorting bars 5 and 6 are formed, respectively. The first shorting bar 5 is formed between the respective gate line pads 3 and the respective gate input pads 7. The respective gate line pads 3 are connected to the first shorting bar 5. The second shorting bar 6 is formed between the respective data line pads 4 and the respective data input pads 8. The respective data line pads 4 are connected to the second shorting bar 6.
In FIG. 1, reference numeral 11, which is not described, represents a laser cutting line.
A TFT-LCD having thin film transistors and pixel electrodes is formed and the array continuity check is performed. A top plate of the TFT-LCD and a bottom plate thereof are then adhered to each other and the shorting bars 5 and 6 are severed from the gate line pads 3 and the data line pads 4 using a laser cutting equipment.
However, the conventional LCD device employing the COG-type mounting method has a disadvantage in that the cost of production increases due to the shorting bar being severed from the respective gate or data line pads using expensive laser cutting equipment.